Add Load Balancer finalizer support

- Always try to remove finalizer upon load balancer cleanup
- Add finalizer prior to load balancer creation (feature gated)
- Cache logic fix-ups
- Event type/message fix-ups
- Use runtime.HandleError() on eaten errors

Co-authored-by: Josh Horwitz <horwitzja@gmail.com>

staging/src/k8s.io/cloud-provider/service/helpers/helper.go

@@ -20,7 +20,7 @@ import (
 	"fmt"
 	"strings"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	utilnet "k8s.io/utils/net"
 )
 
@@ -31,6 +31,11 @@ in order for in-tree cloud providers to not depend on internal packages.
 
 const (
 	defaultLoadBalancerSourceRanges = "0.0.0.0/0"
+
+	// LoadBalancerCleanupFinalizer is the finalizer added to load balancer
+	// services to ensure the Service resource is not fully deleted until
+	// the correlating load balancer resources are deleted.
+	LoadBalancerCleanupFinalizer = "service.kubernetes.io/load-balancer-cleanup"
 )
 
 // IsAllowAll checks whether the utilnet.IPNet allows traffic from 0.0.0.0/0
@@ -100,3 +105,13 @@ func NeedsHealthCheck(service *v1.Service) bool {
 	}
 	return RequestsOnlyLocalTraffic(service)
 }
+
+// HasLBFinalizer checks if service contains LoadBalancerCleanupFinalizer.
+func HasLBFinalizer(service *v1.Service) bool {
+	for _, finalizer := range service.ObjectMeta.Finalizers {
+		if finalizer == LoadBalancerCleanupFinalizer {
+			return true
+		}
+	}
+	return false
+}